The present invention is drawn to a woodworking machine and process for woodworking and more particularly a woodworking machine comprising a pair of serially spaced cutting tools mounted on a pivotable support on a cutting table wherein the cutting tools are adjustable both in unison with respect to the cutting table and relative to each other about a central cutting axis so as to maintain the axis.
Today, in the manufacture of cabinets or the like, the wood or workpiece used generally consists of a laminate material having prefinished surfaces. As a result of the prefinished surfaces it is undesirable to assemble the workpieces by nailing which would result in an unsightly finished product. Therefore, it would be highly desirable and of considerable advantage to be able to assemble furniture without the need of nails, screws, bolts and the like. This may be accomplished by making tongue and groove or dovetail joints, splines and the like for joining the workpieces together.
Heretofore in the woodworking art a single router was used in making both the male and female cuts in a dovetail joint. Traditionally the router was a hand held tool and as a result dimensional integrity was minimal thereby resulting in sloppy fitting joints.
One improvement over the hand held router was to securely mount the router in position on the cutting table. The male cut or tongue was then made by passing a workpiece through the cutter so as to form a slot on the lower surface of the workpiece and thereafter turn the workpiece over and again pass it through the cutter to form a slot on the other surface of the workpiece. Generally, while the joints formed had better dimensional integrity than those produced with a hand held router, the joints were not close fitting or did not fit at all due to the variance in thickness of the workpieces which is not uncommonly as great as an eighth of an inch.
One improved method and apparatus for making dovetail joints or the like is disclosed in U.S. Pat. No. 4,163,465 to Strong. The disclosure teaches mounting a router on a support plate which is adjustable in the vertical direction with respect to a base plate which supports a workpiece. In order to form a tongue in groove or dovetail joint a first workpiece is mounted on the base plate and the female cut or groove is formed by moving the workpiece into cutting engagement with a cutting tool so as to form a groove in the workpiece having a wide base dimension "B" narrowing to a narrow opening dimension "A". In order to make a matching male or tongue cut a second workpiece is mounted on the base plate and the cutting tool is lowered adjacent the base plate. The workpiece is then moved into cutting engagement with the cutting tool so as to cut a slot on the lower portion of the workpiece. The support plate and therefore the cutting tool is then raised a distance equal to dimension "A" plus dimension "B" and the workpiece is again moved into cutting engagement with the cutting tool so as to cut a second slot on the upper portion of the workpiece. The two slots cooperate to form the tongue or male part of the dovetail joint having a dimension "B" and a dimension "A" which slidingly fits in the female cut independent of the relative thicknesses of the various workpieces.
While the aforenoted U.S. Pat. No. 4,163,465 offers significant improvements over those woodworking apparatus previously known in the art, a number of problems have been encountered. It is highly desirable for economic advantages and increased productivity to limit both the number of tool adjustments which must be made to form the male and female parts of a dovetail joint and the number of passes by the workpiece to form said dovetail joint. While snugly fitting joints may be achieved by employing an apparatus such as that disclosed in U.S. Pat. No. 4,163,465 which utilizes a vertically adjustable router, such an apparatus requires multiple tool adjustments and a plurality of workpieces pass to form the male part of the dovetail joint thereby limiting productivity and correspondingly increasing the cost of the finished product.
U.S. Pat. No. 2,790,472 to Fata discloses an apparatus for making tapered dovetails wherein first and second cutters are provided for making the top and bottom cut of a male dovetail in a single cut. The workpiece is held in a pivotable work guide which is fed to the cutters. While the apparatus disclosed by Fata offers a number of advantages it still suffers from numerous serious and costly disadvantages. The first and most serious disadvantage is the fact that the machine is incapable of making both the male and female cuts in a single operation. The female cut is not capable of being made on the Fata apparatus. In addition, a second serious problem with the Fata apparatus is the inability of the machine to make both male and female cuts at any and all desired angles. Furthermore, the apparatus is incapable of making any cuts other than the male portion of a dovetail such as splines, rabbet cuts, mortise, chamfer or the like. Finally, the apparatus of U.S. Pat. No. 2,790,472 is extremely complex, costly to manufacture and susceptible to numerous mechanical malfunctions.
Accordingly, it is a principal object of the present invention to provide an apparatus and method which readily forms the male and female portion of a dovetail joint independent of the thickness of the workpiece without requiring multiple adjustments of the routers.
It is a particular object of the present invention to provide an apparatus having a pair of routers serially mounted on a pivotable support on a cutting table.
It is a further object of the present invention to provide an apparatus having a pair of routers which are readily adjustable both in unison with respect to a workpiece and relative to each other about the cutting axis.
It is a still further object of the present invention to provide an apparatus having a pair of routers mounted in a yoke arrangement and movable relative to each other in a seesaw manner.
It is another still further object of the present invention to provide an apparatus wherein the cutting tools are readily replaceable so that the apparatus is capable of making numerous types of cuts.
Further objects and advantages of the present invention will appear hereinbelow.